(a) We denote the activity state of the \(i-\) th receptor cluster containing \(n\)  trimers of dimers by the variable \(a_i\) , which can take two values. \(a_i=1\)  denotes an active state and \(a_i=0\)  denotes inactive state. The free energy difference \(F\)  between these two states is given by Eq. REF  of the main paper and the probability to find a receptor cluster in active state is \([1+\exp (F)]^{-1}\) . From \(a_i=0\)  state the receptor cluster switches to \(a_i=1\)  state with the rate \(\dfrac{w_a}{1+\exp (F)}\)  and the reverse transition happens with a rate \(\dfrac{w_a \exp (F)}{1+\exp (F)}\)  [1]}. The choice of these rates is based on local detailed balance [1]}. The parameter \(w_a\)  is the characteristic time-scale of the transition [3]}.
